1. Technical Field
The present invention relates to a piezo vibration module.
2. Description of the Related Art
Generally, in portable electronic devices, such as a portable phone, an E-book terminal, a game machine, a PMP, and the like, a vibration function has been variously utilized.
In particular, a vibration generating apparatus for generating the vibration has been mainly mounted in the portable electronic device to be used as an alert function that is a silent receiving signal.
With the multi-functionalization of the portable electronic device, a demand for small, integrated, and multi-functional vibration generating apparatus have increased.
Further, with the recent demand by users to conveniently use the portable electronic device, a touch type device performing an input by touching the portable electronic device has been adopted generally.
A concept of a currently prevalently used haptic device includes a concept of reflecting intuitive experience of an interface user and diversifying feedback for a touch, in addition to a concept of performing an input by a touch.
In general, the haptic device is repeatedly deformed by being expanded and/or contracted depending on the application of an external power supply of a piezo element to provide vibrations. In connection with this, a vibration generator adopting the piezo element is disclosed in Patent Document 1.
The piezo vibration apparatus disclosed in Patent Document 1 generates vibrations by vertically displacing both ends as much as possible using a central portion as a vibration point of application depending on a polarity change of applied voltage or generates vibrations by vertically displacing both ends as much as possible using a central portion as a vibration point of application.
The piezo vibration apparatus includes a substrate, a piezo element layer in which a piezo material is laminated on one surface or both surfaces of the substrate, and an electrode layer for applying voltage to upper and lower surfaces of the piezo element layer. However, the piezo vibration apparatus according to the Patent Document 1 does not disclose in detail the piezo element layer and a current applying method. As known to a person with ordinary skill to which the present invention pertains, when the piezo element layer is applied with a signal from the substrate, a phenomenon that the piezo element layer is separated from the piezo element soldered to an end of the substrate due to a repetitive vibration movement of the piezo element layer often occurs. In detail, a crack may occur due to a sudden rigidity change of a pattern applied with lead of a PCB and a portion at which a pattern is not formed, for example, at the time of external impact. The crack may cause a short-circuit phenomenon at the PCB and an external electrode of the piezo element. Further, since the soldered portion is generally exposed to the outside, there is the inconvenience of enclosing the soldered portion with an insulating tape, and the like, so as to prevent a short-circuit risk.
Herein, the substrate may be a PCB substrate, a plastic substrate on which an electrode pattern is printed, and the like, or may be made of metal, and the like.